1. Field of the Invention
This invention relates to cigarette lighters, and more particularly to flame adjustment devices for liquefied gas lighters.
2. Description of the Prior Art
A feature of liquefied gas cigarette lighters that has contributed to their wide popularity is the provision of means by which the height of the flame they produce can be conveniently and easily adjusted to suit the desires of different users and the requirements of various circumstances in which the lighters are employed. While the adjustment means may take on various forms of construction, at least with reference to the internal working valve parts, it is convenient to adopt a design which includes a rotatable valve adjustment member extending exteriorly from a valve well, which adjustment member may be coupled to an adjustment mechanism. Manual rotation of the adjustment mechanism then turns the valve adjustment member, which modifies the relationship of the internal working valve parts so as to regulate the rate of gas flow and thereby control flame height.
For safety and convenience, it is also desirable in the manufacture of an adjustable lighter, to fix the maximum and minimum allowed flame height settings. A built-in maximum flame height setting provides a safety factor, avoiding a dangerously high flame, which can catch the user unawares or cause excess still-liquid flaming droplets of fuel to be spattered about. A build-in minimum setting prevents one possible cause of user dissatisfaction by making it possible to reduce fuel flow to a rate at which a flame can not be sustained.
Some commercially-available liquefied gas lighters provide maximum and minimum flame height limits by incorporating stop means to limit rotation of the valve adjustment member or coupled adjustment mechanism. In a typical form of construction the lighter body may include a fixed stop which engages a moving stop or abutment surface on the adjustment mechanism to limit rotation thereof. The built-in flame adjustment in the manufacture of such a lighter would be accomplished typically by igniting a flame and rotating the valve adjustment member to the desired maximum flame height. Then the adjustment mechanism would be attached to the valve adjustment member with the adjustment mechanism oriented so that a movable stop on the adjustment mechanism is flush against a fixed stop on the lighter body, i.e. the adjustment mechanism is attached while positioned at one limit of its rotation. By design the opposite rotational limit of the adjustment mechanism provides the minimum flame height setting. Although such a construction prevents misuse by the consumer, it has an inherent drawback in that the adjustment mechanism must be attached to the lighter assembly after the setting is made, while the valve adjustment member is in one limiting position. This is difficult to accomplish in high-speed automated processes.
The adjustment mechanism is normally either a milled wheel provided with a grooved central opening which fits around a matching section of the valve adjustment member, the milled wheel therefore rotating with the valve adjustment member, but free to move in translation; or a lever with one end in the form of a flexible fork resting upon the grooved periphery of the valve adjustment member. In both cases, the separation between two adjacent engagement positions of the adjustment mechanism with respect to the valve adjustment member depends upon the angular spacing of the grooves. This leads to a lack of precision in adjusting the minimum and/or maximum flame height, because only a limited number of engagement positions are available.
Moreover, it is not possible to make the adjustment mechanism and the valve adjustment member as a single part, since the presence of stops on the adjustment mechanism would prevent it from being screwed into the valve well.